The present invention is directed to braided wires having three or more strands, and in particular to braided wires used in catheter construction.
A catheter is a tool used to deliver surgical tools and medical devices to a surgical site via the smallest possible opening into the body. A wire braid is a common structural component of a medical catheter device.
There is advantage in making the wall thickness of the catheter as thin as possible. This permits the largest possible inside catheter diameter while maintaining the smallest possible outside catheter diameter. The catheter must fit within the smallest possible blood vessels in order to access as much of the body as possible, while still having maximal internal capacity to deliver tools and devices to the surgical site.
The catheter must also be able to transmit accurately, the input forces, radial and axial, required to manipulate the catheter and the enclosed surgical tools and supplies. That is the function of the wire braid, which is commonly enclosed between various inner and outer layers of polymeric materials.
U.S. Pat. No. 8,795,255 is directed to a catheter with composite stiffener, and discusses the problems associated with catheter stiffness. For some uses, catheters should be fairly stiff at their proximal end so as to allow the pushing and manipulation of the catheter as it progresses through the body, and yet should be sufficiently flexible at the distal end to allow passage of the catheter tip through the loops and increasingly smaller blood vessels in which the catheter is used. U.S. Pat. No. 5,897,567 also speaks to stiffness, which is a primary attribute desired in the catheter construction. Both of these patents are incorporated by reference for their teachings related to stiffness and flexibility particularly in catheter construction. However, better solutions to obtain the desired balance between stiffness (particularly torsional stiffness) and flexibility are needed, particularly for use in catheter construction.
Separate from the catheter arts, there is archeological evidence that electroplating was conducted as far back as the Bronze Age. In the more recent 20-30 years, an innovation on the theme is the electroless plating chemical reaction. The important distinction is that the electroless nickel chemistries existing today almost always are alloyed with between 3 and 12% phosphorous. This is for increased corrosion resistance on the deposit, such as for use in car bumpers. The phosphorous addition also makes the electroless plated deposit more ductile. As the original chemical reaction was electroplating, the industry may generically use the term “electroplating” as referring to either electroplating or electroless-plating or both.